iPSCs derived sEVs ameliorate NK cell senescence by targeting CISH-STAT3

Natural killer (NK) cells, essential components of the innate immune system, undergo subtype changes with aging that diminish their cytotoxic and tumor surveillance functions. Recent reports indicate that small extracellular vesicles (sEVs) derived from stem cells could ameliorate age-related diseases, while their effects on NK cell senescence remain unexplored.

We administered induced pluripotent stem cell(iPSC) derived sEVs via tail vein injection for 6 months to naturally aged mouse models. Then we detected a senescent phenotype of splenic NK cells based on a series recognized markers in aged mice. To further investigate the impact of iPSC-sEVs mediated rejuvenation on NK cell function in vivo, purified splenic NK cells from iPSC-sEVs or vehicle-treated mice were co-injected subcutaneously with B16 tumor cells to establish co-inoculation models. In vitro, we used D-gal induced NK92 aged model and conducted transcriptome analysis on the cells. Furthermore, NK92 cells overexpressing CISH were used to explore the mechanism by which iPSC-sEVs improve NK92 cells senescence. Further we conducted a mass spectrometry analysis of the substances in iPSC-sEVs and performed bioinformatics analysis.

iPSC-sEVs treatment partially reversed these immunosenescence phenotypes in aged mice models. In splenic NK and B16 tumor cells co-inoculation models, iPSC-sEVs-NK cells exhibited significantly enhanced cytotoxicity against tumor cells and the ability to recruit T cells. Mechanistic studies suggest that iPSC-sEVs inhibit the upregulation of CISH in senescent NK cells, subsequently activating p-STAT3, which is involved in regulating NK cell senescence and cytotoxicity. Overexpression of CISH significantly suppresses STAT3 phosphorylation and accelerates NK92 cell senescence. Proteomic analysis indicates that iPSC-sEVs modulate the CISH-STAT3 signaling pathway by delivering RNA binding proteins.

In summary, our study shows that iPSC-sEVs effectively rejuvenate senescent NK cells by partially suppressing CISH expression and promoting STAT3 phosphorylation. As a cell-free therapeutic agent, iPSC-sEVs represent a promising strategy for treating cancer in the elderly and other inflammatory senescence-related diseases.